diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0969286..9e522ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 # CHANGELOG
 ## not released
+- parser: Added support for reference_timestamp with tzinfo (fixes #84)
 - parser: Fixed textual altitude part (fixes #81)
 - parser: Skip keys where value is "None"
 
diff --git a/ogn/parser/utils.py b/ogn/parser/utils.py
index 7115b37..4573404 100644
--- a/ogn/parser/utils.py
+++ b/ogn/parser/utils.py
@@ -1,4 +1,4 @@
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 
 FEETS_TO_METER = 0.3048             # ratio feets to meter
 FPM_TO_MS = FEETS_TO_METER / 60     # ratio fpm to m/s
@@ -11,7 +11,7 @@ def parseAngle(dddmmhht):
     return float(dddmmhht[:3]) + float(dddmmhht[3:]) / 60
 
 
-def createTimestamp(time_string, reference_timestamp=None):
+def createTimestamp(time_string, reference_timestamp):
     if time_string[-1] == "z":
         dd = int(time_string[0:2])
         hh = int(time_string[2:4])
@@ -20,7 +20,8 @@ def createTimestamp(time_string, reference_timestamp=None):
         result = datetime(reference_timestamp.year,
                           reference_timestamp.month,
                           dd,
-                          hh, mm, 0)
+                          hh, mm, 0,
+                          tzinfo=timezone.utc if reference_timestamp.tzinfo is not None else None)
 
         if result > reference_timestamp + timedelta(days=14):
             # shift timestamp to previous month
@@ -36,7 +37,8 @@ def createTimestamp(time_string, reference_timestamp=None):
         result = datetime(reference_timestamp.year,
                           reference_timestamp.month,
                           reference_timestamp.day,
-                          hh, mm, ss)
+                          hh, mm, ss,
+                          tzinfo=timezone.utc if reference_timestamp.tzinfo is not None else None)
 
         if result > reference_timestamp + timedelta(hours=12):
             # shift timestamp to previous day
diff --git a/tests/parser/test_utils.py b/tests/parser/test_utils.py
index 270075e..01b011c 100644
--- a/tests/parser/test_utils.py
+++ b/tests/parser/test_utils.py
@@ -1,5 +1,5 @@
 import unittest
-from datetime import datetime
+from datetime import datetime, timezone
 
 from ogn.parser.utils import parseAngle, createTimestamp
 
@@ -33,6 +33,13 @@ class TestStringMethods(unittest.TestCase):
 
         self.proceed_test_data(test_data)
 
+    def test_createTimestamp_tzinfo(self):
+        test_data = [
+            ('000001h', datetime(2020, 9, 10, 0, 0, 1, tzinfo=timezone.utc), (datetime(2020, 9, 10, 0, 0, 1, tzinfo=timezone.utc)))
+        ]
+
+        self.proceed_test_data(test_data)
+
 
 if __name__ == '__main__':
     unittest.main()